In a statement published on Twitter, a Liverpool spokesman wrote: "Liverpool Football Club was this morning saddened to hear of the death of prominent Hillsborough campaigner Anne Williams. RIP Anne."

Williams lost her 15-year-old son Kevin in the Hillsborough disaster, and always maintained that the original 1991 inquest into the deaths of the victims was flawed.

Coroner Stefan Popper ruled that none of the victims could have been saved after 3.15pm on April 15, 1989, and recorded verdicts of accidental death.

Mrs Williams and other campaigners believed that verdict prevented a proper investigation into the culpability of the police and emergency services on the day of the disaster.

She tracked down witnesses who suggested that her son had still been alive at 4pm on the day of the tragedy, but her calls for fresh inquests were rejected by both the UK government and the European Court of Human Rights.

The original inquest verdicts were then quashed at the High Court in December following an application by Attorney General Dominic Grieve. A hearing to prepare ground for fresh inquests will be held in London on April 25.

In addition, the Independent Police Complaints Commission - the UK's police watchdog - is conducting an inquiry into the police's role in the disaster to ascertain whether criminal charges will be brought against individual officers.

Sheila Coleman, spokeswoman of the Hillsborough Justice Campaign, told the Liverpool Echo: "I am immensely saddened by the death of Anne Williams. She paid the ultimate price for her fight for justice. Quite simply, she was an inspiration.

"When I saw Anne on Monday, I knew it was the last time I would see her alive. It was very emotional. Anne was in her wheelchair outside Anfield surrounded by people who had supported her fight for all the years.

"Anne didn't want to die. We had been looking forward to continuing the fight but then she was diagnosed with that dreadful illness. It was only her sea of will power that got her to the service on Monday. She was determined to be there for her son and fulfil her duty. You could tell she was weary."

Everton paid their own tribute on Twitter. It read: "The thoughts of everyone at Everton are with the family of Anne Williams, who sadly passed away this morning."